CN102449290A - Method for determining a position setpoint of a bypass actuator intended for a turbocharger - Google Patents

Abstract

The invention relates to a method for a turbocharger (1, 11) intended for a heat engine (4), said turbocharger (1, 11) comprising a turbine (2, 12), a compressor (3, 13), and means for controlling a gas flow (W) that does not pass through said turbine (2, 12)_act) By-pass actuators (15, 16). The method includes determining the bypass execution according toPosition setpoint (alpha) of the running gear (15, 16)_sp) The steps of (1): compression ratio set Point (PR)_c，sp) Compression ratio measurement (PR)_c，m) Flow measurement (W) by the compressor (3, 13)_c，m) A pressure measurement P downstream of the turbine (2, 12)_dtA pressure measurement P downstream of the compressor (3, 13)_dcA temperature measurement T upstream of the turbine (2, 12)_utAnd a temperature measurement T upstream of the compressor (3, 13)_uc. The invention can be used to control a supercharging device having one or two turbochargers.

Description

Method for determining the position set point of a bypass actuator intended for use in a turbocharger

technical field

The present invention relates to engine management and, more particularly, to operating a turbocharger-type supercharger using a method of determining a turbo bypass actuator position set point from a compression ratio set point.

Background technique

The invention applies to supercharging installations comprising a fixed geometry turbocharger or alternatively having two such turbochargers mounted in series.

As the performance of the boosted engine increases, the boost pressure level increases and the demand on the turbocharger increases. It is important to run these turbochargers as carefully as possible to avoid turbocharger damage while improving the responsiveness of the vehicle under acceleration.

As emission standards become more stringent than ever, the amount of particulate matter emitted by engines must be lower than ever. A particulate filter (or PF) is a solution to reduce the amount of particulate matter emitted into the environment. A particle filter consists of a set of microchannels in which most particles are trapped. Once the filter is full, it must be emptied by burning off the particles, a phase called "regeneration". Regeneration can be achieved using heating equipment or through special engine settings. A particulate filter is placed in the exhaust pipe downstream of the low-pressure turbine.

The introduction of such equipment results in increased exhaust back pressure. The more particles the filter carries, the greater this back pressure. This exhaust backpressure becomes apparent relative to the turbocharger by reducing the expansion ratio, resulting in reduced power from the exhaust to the turbine and a reduction in engine performance. To achieve the same level of performance, the expansion ratio must be maintained by increasing the pressure upstream of the turbine. The increase in pressure upstream of the turbine is achieved by proper closure of the bypass actuator. The booster equipment can be operated using commands issued to these actuators.

In the field of operating such twin turbochargers, the applicant's company has developed a dual loop control method for simultaneous operation of two turbochargers, in patent application FR 08 53686 filed on June 4, 2008 The method is described. Such systems bring considerable performance, but require an exhaust pressure sensor upstream of the high pressure turbine. Installing such sensors is expensive. The present invention proposes to dispense with this sensor.

Contents of the invention

For this reason, when there is only one turbocharger, the control method advantageously uses the compressor compression ratio variable to operate one turbocharger. Furthermore, when there are two turbochargers, the method replaces dual-loop control with a handler that selects which turbocharger to operate, controlling one or the other turbocharger at any given moment. compressor.

The subject of the invention is a method for supercharging an internal combustion engine in a turbocharger comprising: a turbine driven by the exhaust gas; a compressor driven in rotation by the turbine in order to compress the intake air and a bypass actuator for bypassing the turbine so that it can control the flow of air not passing through the turbine, the method determining a position set point for the bypass actuator based on: a compression ratio setting set point, compression ratio measurement, flow measurement of flow through the compressor, pressure measurement of pressure downstream of the turbine, pressure measurement of pressure downstream of the compressor, temperature measurement of temperature upstream of the turbine, and A temperature measurement of the temperature upstream of the compressor.

According to another feature of the invention, determining the position setpoint of the bypass actuator comprises:

- determining an expansion ratio setpoint from said compression ratio setpoint and said compression ratio measurement,

- Determination of the position setpoint of the bypass actuator on the basis of the thus determined expansion ratio setpoint.

According to another feature of the invention, determining the position setpoint of the bypass actuator from the expansion ratio setpoint uses an inverse actuator model.

According to another characteristic of the invention, before using the reverse actuator model, the expansion ratio set point is saturated according to the maximum allowable pressure downstream of the turbine using the following formula:

${\mathrm{PR}}_{t,\mathrm{sp},\mathrm{sat}}=\min ({\mathrm{PR}}_{t,\mathrm{sp}},\frac{P_{\mathrm{dt},\max }}{P_{\mathrm{dt}}}),$ in

PR _t,sp,sat is the expansion ratio set point after saturation,

PR _t,sp is the expansion ratio set point before saturation,

_Pdt is the pressure downstream of the turbine,

P _dt,max is the maximum acceptable pressure downstream of the turbine,

The saturated compression ratio setpoint value will then replace the initial compression ratio setpoint value.

According to another feature of the invention, the expansion ratio set point is equal to the open-loop expansion ratio set point calculated by the pre-positioning module based on the compression ratio set point and calculated by the first controller module based on the compression ratio set point. The error between the set point and the compression ratio measurement is calculated as the sum of the closed loop expansion ratio set point.

According to another feature of the invention, the position set point of the bypass actuator is equal to the open loop position set point calculated from the compression ratio set point and set by the second controller module according to the compression ratio The error between the point and the compression ratio measurement is calculated as the sum of the closed loop position set point.

According to another characteristic of the invention, determining said open loop position setpoint comprises the steps of:

- determination of an open loop expansion ratio setpoint by a prepositioning module based on said compression ratio setpoint,

- Determining the open loop position setpoint from the thus determined open loop expansion ratio setpoint using the inverse actuator model.

According to another characteristic of the invention, said position setpoint is finally saturated using the following formula:

α _sp,sat =min(α _sp ,α _sp,max ), where

α _sp,sat is the position set point after saturation,

α _sp is the position set point before saturation,

α _sp,max is the maximum position set point.

According to another feature of the invention, said maximum position setpoint is determined from said open loop expansion ratio setpoint using an inverse actuator model.

According to another feature of the invention, said open loop expansion ratio set point is saturated according to the maximum allowable pressure downstream of said turbine using the following formula before applying the inverse actuator model used to determine said maximum position set point :

${\mathrm{PR}}_{t,\mathrm{sp},\mathrm{sat}}=\min ({\mathrm{PR}}_{t,\mathrm{sp},\mathrm{ol}},\frac{P_{\mathrm{dt},\max }}{P_{\mathrm{dt}}}),$ in

PR _t,sp,sat is the expansion ratio set point after saturation,

PR _t,sp is the expansion ratio set point before saturation,

_Pdt is the pressure downstream of the turbine,

P _dt,max is the maximum acceptable pressure downstream of the turbine,

The saturated expansion ratio setpoint value will then replace the initial open loop expansion ratio setpoint value.

According to another feature of the present invention, the pre-positioning module includes the following steps:

- determining a corrected flow measurement of the flow of intake air through the compressor from the flow measurement of the flow of intake air through the compressor using the following formula:

$W_{c,m,\mathrm{cor}}=W_{c,m}\&Center\; Dot;\sqrt{\frac{T_{\mathrm{uc}}}{T_{c,\mathrm{ref}}}}\&Center\; Dot;\frac{P_{c,\mathrm{ref}}}{P_{\mathrm{dc}}},$ in

W _c,m,cor is the corrected flow measurement of the flow of intake air through the compressor,

W _c,m is the air flow measurement of the flow of intake air through the compressor,

T _uc is the temperature upstream of the compressor,

P _uc is the pressure upstream of the compressor,

Tc _,ref is the reference temperature of the compressor,

P _c,ref is the reference pressure of the compressor,

- determining a corrected speed set point for said compressor using a function of said compression ratio and a corrected flow rate of intake air through said compressor, said function being defined by a two-dimensional map,

- determining the speed set point from the corrected speed set point for said compressor using the following formula, $N_{\mathrm{sp}}=N_{\mathrm{sp},\mathrm{corc}}\sqrt{\frac{T_{\mathrm{uc}}}{T_{c,\mathrm{ref}}}},$ in

N _sp is the speed set point of the turbocharger,

Nsp _,corc is the corrected speed set point of the turbocharger with respect to the compressor,

T _uc is the temperature upstream of the compressor,

Tc _,ref is the reference temperature of the compressor,

- using a function of the turbocharger's corrected speed set point for the compressor and the corrected air flow set point for the flow of intake air through the compressor, according to the turbocharger Compressor with respect to the corrected speed set point of the compressor and the corrected air flow set point of the flow of intake air through the compressor to calculate the efficiency of the compressor, the function is given by two dimension map definition,

- Calculate the compressor power set point using the following formula,

$h_{c,\mathrm{sp}}=W_{c,m}{\mathrm{<figure-callout\; id="1"\; label="Cp\; c"\; filenames="HDA0000113008610000012.png,HDA0000113008610000031.png"\; state="\{\{state\}\}">Cp</figure-callout>}}_c\frac{1}{{\mathrm{\&eta;}}_c}{T}_{\mathrm{uc}}({\mathrm{PR}}_{c,\mathrm{sp}}^{\frac{{\mathrm{\&gamma;}}_c-1}{{\mathrm{\&gamma;}}_c}}-1),$ in

Hc _,sp is the power set point of the compressor,

W _c,m is the air flow measurement of the flow of intake air through the compressor,

_ηc is the efficiency of the compressor,

T _uc is the temperature upstream of the compressor,

PR _c,sp is the compression ratio set point of the compressor,

Cp _c is the first thermodynamic constant of the intake air,

γ _c is the second thermodynamic constant of the intake air,

- Calculation of the turbine power set point using the following formula: H _t,sp =H _c,sp , where

Ht _,sp is the power set point of the turbine,

Hc _,sp is the power set point of the compressor,

- Determining a corrected speed set point for said turbine from said speed set point using the following formula:

$N_{\mathrm{sp},\mathrm{cort}}=N_{\mathrm{sp}}\sqrt{\frac{T_{t,\mathrm{ref}}}{T_{\mathrm{out}}}},$ in

N _sp is the speed set point of the turbocharger,

Nsp _,cort is the corrected speed set point of the turbocharger for the turbine,

T _ut is the temperature upstream of the turbine,

T _t,ref is the reference temperature of the turbine,

- Calculate the open loop expansion ratio set point using the following formula

${\mathrm{PR}}_{t,\mathrm{sp},\mathrm{ol}}=f^{-1}(\frac{h_{c,\mathrm{sp}}}{{\mathrm{Cp}}_t\&CenterDot;T_{\mathrm{out}}\&Center\; Dot;\frac{P_{\mathrm{dt}}}{P_{t,\mathrm{ref}}}\&Center\; Dot;\sqrt{\frac{T_{t,\mathrm{ref}}}{T_{\mathrm{out}}}}},N_{\mathrm{sp},\mathrm{cort}}),$ in

PR _t,sp,ol is the open loop expansion ratio of the turbine,

Ht _,sp is the power set point of the turbine,

Nsp _,cort is the corrected speed set point of the turbocharger for the turbine, and

F is a function defined by a two-dimensional map and obtained by inversion of the following equation:

$h_{t,\mathrm{sp}}=W_{t,\mathrm{sp}}\&CenterDot;{\mathrm{Cp}}_t\&CenterDot;{\mathrm{\&eta;}}_t\&Center\; Dot;T_{\mathrm{out}}[1-{\left(\frac{1}{{\mathrm{PR}}_{t,\mathrm{sp},\mathrm{ol}}}\right)}^{\frac{{\mathrm{\&gamma;}}_t-1}{{\mathrm{\&gamma;}}_t}}],$ in

Ht _,sp is the power set point of the turbine,

PR _t,sp,ol is the open loop expansion ratio of the turbine,

Cp _t is the first thermodynamic constant of the exhaust gas,

_γt is the second thermodynamic constant of the exhaust gas,

_ηt is the efficiency of the turbine, expressed as a function of the turbocharger's corrected speed setpoint for the turbine and the open-loop expansion ratio setpoint, given by the two-dimensional mapping definition,

W _t,sp is the flow setpoint of the flow of exhaust gas through the turbine and is determined by:

$W_{t,\mathrm{sp}}=W_{t,\mathrm{sp},\mathrm{cor}}\&Center\; Dot;\sqrt{\frac{T_{t,\mathrm{ref}}}{T_{\mathrm{out}}}}\&Center\; Dot;\frac{P_{\mathrm{dt}}}{P_{t,\mathrm{ref}}},$ in

W _t,sp is the flow set point of the flow of exhaust gas through the turbine,

W _t,sp,cor is the corrected flow set point for the flow of exhaust gas through the turbine, with the corrected speed set point of the turbocharger for the turbine and the open loop Expressed as a function of the expansion ratio set point, the function is defined by a two-dimensional map,

T _ut is the temperature upstream of the turbine,

T _t,ref is the reference temperature of the turbine,

_Pdt is the pressure downstream of the turbine,

Pt _,ref is the reference pressure of the turbine.

According to another characteristic of the invention, said first controller module or respectively said second controller module is a regulator configured to cancel said error.

According to another characteristic of the invention, said regulator uses fuzzy logic rules.

According to another characteristic of the invention, said regulator comprises a proportional-integral-derivative (PID) module.

According to another characteristic of the invention, the bypass actuator for bypassing said turbine is modeled by the Saint Venant equation using the following formula:

$W_{\mathrm{act}}=S_{\mathrm{act}}\frac{P_{\mathrm{dt}}}{\sqrt{T_{\mathrm{dt}}}}\&Center\; Dot;\mathrm{\&psi;}\left(\mathrm{PR}\right),$ in

PR means input parameters, namely, the following parameters respectively:

PR _{t, sp} expansion ratio set point,

PR _{t, sp, ol} open loop expansion ratio set point,

PR _t,sp,ol,sat open loop expansion ratio set point after saturation,

W _act is the flow through the actuator,

S _act is the cross-sectional area of the actuator,

_Pdt is the pressure downstream of the turbine,

_Tdt is the temperature downstream of the turbine,

ψ is a function of the variable X and is defined by:

$\mathrm{\&psi;}\left(x\right)=\sqrt{\frac{2{\mathrm{\&gamma;}}_t}{R({\mathrm{\&gamma;}}_t-1)}}\sqrt{x^{\frac{-2}{{\mathrm{\&gamma;}}_t}}-x^{\frac{-({\mathrm{\&gamma;}}_t-1)}{{\mathrm{\&gamma;}}_t}}},$ in

_γt is the first thermodynamic constant of the exhaust, equal to 1.4,

R is the universal gas constant, equal to 287J/kg/K.

According to another feature of the invention, wherein the flow through said actuator is determined using the formula W _act =W _c,m -W _t,sp , where

W _c,m is a measure of the flow through the compressor,

Wt _,sp is the flow set point for the flow through the turbine.

According to another feature of the invention, said cross-sectional area of said actuator is mapped as a function of said position setpoint and said expansion ratio setpoint of said actuator.

The invention also relates to a method for a fixed-geometry dual supercharging device for supercharging an internal combustion engine, said device comprising:

- a high-pressure first turbocharger comprising: a high-pressure turbine driven by exhaust gas discharged from the internal combustion engine; a high-pressure compressor rotated by the high-pressure turbine to compress intake air entering the internal combustion engine; and a high-pressure bypass implementation a mechanism for bypassing the high pressure turbine such that it can control the flow of air not passing through the high pressure turbine,

- a low-pressure second turbocharger comprising: a low-pressure turbine driven by exhaust gas from said internal combustion engine via said high-pressure turbine or said high-pressure bypass actuator; a low-pressure compressor driven in rotation by said low-pressure turbine for compressing intake air entering the internal combustion engine via the high pressure compressor; and a low pressure bypass actuator for bypassing the low pressure turbine so that it can control the flow of air not passing through the low pressure turbine, and

- a bypass valve for the high pressure compressor to allow selective bypassing of the high pressure compressor in order to connect the low pressure compressor directly to the engine,

The method includes determining a set point for controlling the high pressure bypass actuator and a set point for controlling the low pressure bypass actuator based on: a high pressure pressure ratio set point, a low pressure pressure ratio set point point, high-pressure pressure ratio measurement, low-pressure pressure ratio measurement, air flow measurement of air flow through the high-pressure and low-pressure compressors, pressure measurement downstream of the high-pressure turbine and the low-pressure turbine respectively, at the high-pressure compressor and pressure measurement downstream of said low pressure compressor, temperature measurement upstream of said high pressure turbine and said low pressure turbine respectively, and temperature measurement upstream of said high pressure compressor and said low pressure compressor respectively, said method comprising step:

- selecting by means of a processing module which of said high pressure bypass actuators and said low pressure bypass actuators is to be controlled,

- Selecting the high pressure bypass actuator position set point accordingly based on the high pressure compression ratio set point and the high pressure compression ratio measurement, or based on the low pressure compression ratio, as described in any of the previous embodiments The set point and low pressure compression ratio measurements determine the position set point of the low pressure bypass actuator.

According to another feature of the present invention, the selection step is performed by the processing module according to the following rules:

- when the speed of the engine is below a threshold, the high pressure bypass actuator is operated, the bypass valve of the high pressure compressor is forced closed and the low pressure bypass actuator is forced closed,

- When the speed of the engine is above a threshold, the low pressure bypass actuator is operated, the bypass valve of the high pressure compressor is forced open and the high pressure bypass actuator is forced open.

According to another characteristic of the invention, the threshold speed of said engine is equal to 2750 rpm.

Description of drawings

Other features, details and advantages of the invention will become more apparent from the following detailed description, given by way of indication when taken in conjunction with the accompanying drawings, which are:

- Figure 1 shows an internal combustion engine with a turbocharger for supercharging;

- figure 2 shows an internal combustion engine with a charging device comprising two turbochargers;

- Figure 3 is a block diagram of a "tandem" embodiment of the method according to the invention;

- Figure 4 is a block diagram of a "parallel" embodiment of the method according to the invention;

- Figure 5 is a block diagram introducing two modules connected in series or in parallel;

- Figures 6 and 7 are respectively a map and a table defining the values of the function f1 of the high-pressure turbocharger;

- Figures 8 and 9 are respectively a map and a table defining the values of the function f1 of the low-pressure turbocharger;

- Figures 10 and 11 are respectively a map and a table defining the values of the function f2 of the high-pressure turbocharger;

- Figures 12 and 13 are respectively a map and a table defining the values of the function f2 of the low-pressure turbocharger;

- Figures 14 and 15 are respectively a map and a table defining the values of the function F ^-1 of the high-pressure turbocharger;

- Figures 16 and 17 are respectively a map and a table defining the values of the function F ^-1 of the low-pressure turbocharger;

- Figures 18 and 19 show the results obtained using modules in series and in parallel, respectively.

To make the instructions, block diagrams and especially the formulas easier to understand, the following symbols are used:

variable

N: speed (of turbocharger),

PR: pressure ratio (compression ratio in case of compressor, expansion ratio in case of turbine),

W: flow rate,

P: pressure,

H: power,

T: temperature,

η: efficiency,

RM: engine speed,

Cp: thermodynamic constant, i.e. specific heat capacity at constant pressure,

Cv: thermodynamic constant, that is, the specific heat capacity at constant volume,

γ: thermodynamic constant, which is equal to the coefficient of Cp/Cv,

J: moment of inertia (of the turbocharger) or second moment of area,

suffix

c: compressor,

t: turbo,

sp: set point,

m: measured, observed or simulated,

cor: corrected,

cort: Cortex-related cortex,

corc: Corrected for the compressor,

ref: benchmark

u: upstream

d: downstream

ol: open loop

cl: closed loop

sat: saturated

HP: high pressure

BP: low pressure

Detailed ways

FIG. 1 shows the context of the invention in the context of a single turbocharger 1 . The internal combustion engine 4 typically receives air 5 via an intake duct 6 . The engine 4 produces exhaust gas 7 which is expelled via an exhaust passage 8 . The turbocharger 1 for supercharging makes it possible to increase the air volume 5 received by the internal combustion engine 4 . To this end, turbocharger 1 includes a turbine 2 and a compressor 3 . Turbine 2 is fluidly connected to exhaust duct 8 to be driven by exhaust gas 7 from internal combustion engine 4 . The turbine 2 is mechanically connected to a compressor 3 which it drives in rotation. Compressor 3 is fluidly connected to intake passage 6 such that compressor 3 compresses intake air 5 before it enters internal combustion engine 4 . The turbine 2 can be isolated using a bypass actuator 15 . Compressor 3 may be isolated using bypass valve 14 . Reference numeral 9 contains a sensor for measuring the flow W _c,m of the intake air 5 .

FIG. 2 shows the environment of the invention in the case of two turbochargers 1 , 11 . The high-pressure first turbocharger 1 is identical to the previously described turbocharger and comprises a high-pressure turbine 2, a high-pressure compressor 3 and a proportionally controlled high-pressure bypass actuator 15, making it possible to set the flow that does not pass through the high-pressure turbine 2 . The low-pressure second turbocharger 11 is connected in series with the first turbocharger 1 . The low-pressure turbine 12 is driven by the exhaust gas 7 leaving the downstream side of the high-pressure turbine 2 or the high-pressure bypass actuator 15 when it is at least partially forced open. On the outlet side of the low-pressure turbine 12 the exhaust gas 7 is directed to the exhaust pipe. The low pressure turbine 12 is mechanically connected to a low pressure compressor 13 which it drives in rotation. The low-pressure compressor 13 receives air from the air filter and compresses the air, which is then passed on to the upstream side of the high-pressure compressor 3 . If the open/close bypass valve 14 is open, the low pressure compressor 13 delivers air directly to the engine 4 via the intake duct 6 .

Two (ie high pressure 15 and low pressure 16 ) bypass actuators capable of proportional control are located between the upstream side and the downstream side of the high pressure turbine 2 and the low pressure turbine 12 respectively. Also, an open/close compressor bypass valve 14 is located between the upstream side and the downstream side of the high pressure compressor 3 . These three devices provide control of the overall pressurization system 20 .

However, the dual loop control of the prior art operates both bypass actuators 15, 16 simultaneously, wishing to cancel the exhaust pressure P _{ut upstream of the high pressure turbine 2, and the operation of the HP} sensor would not allow such means of control.

One of the principles of the invention is to operate only one turbocharger 1 , 11 at a time by acting on the corresponding bypass actuator 15 , 16 .

对于涡轮2、12，此压力比称为膨胀比PR_t并等于

According to the invention, the central block of the method comprises the step of determining the position setpoint α _sp of the bypass actuator 15 , 16 from the compression ratio setpoint PR _c,sp and the compression ratio measurement PR _c,m . Two pressure ratios PR can be defined as the ratio of upstream pressure _Pu to downstream pressure _Pd . For the compressors 3, 13, this pressure ratio is called the compression ratio PR _c and is equal to

For turbines 2, 12, this pressure ratio is called the expansion ratio PR _t and is equal to

Said central module receives as input the compression ratio setpoint PR _{c, sp} on the basis of which the parameters are determined in open loop. To refine the method, loop closure parameters are also determined. To this end, the method loops back on parameters indicative of the response of the system 20 . The parameter of this measurement may be the compression ratio measure PR _c,m , or the difference ε _PRc of said compression ratio (calculated as ε _PRc =PR _c,sp −PR _c,m ), which are equivalent.

This central module can be operated in various modes of embodiment. Two exemplary embodiment modes are presented here. These two modes use the same or similar modules organized in different ways. A first "series" mode of the embodiment is shown in FIG. 3 . A second "parallel" mode of the embodiment is shown in FIG. 4 .

Referring to Fig. 3, in series mode, the step of determining the position set point α _sp of said bypass actuator 15, 16 can be broken down into: a first step, by the units 21, 22, 23 according to the position provided at the input The compression ratio set point PR _c,sp , the compression ratio measurement PR _c,m or the difference ε _PRc determines the expansion ratio set point PR _t,sp ; followed by a second step, in unit 25 and, where appropriate, in unit 24 according to This determined expansion ratio setpoint PR _t,sp determines the position setpoint α _sp of the bypass actuator 15 , 16 . Determining the position setpoint α _{sp of the bypass actuator 15 , 16 from the expansion ratio setpoint PR t, sp} uses the inverse actuator model located in the unit 25 . This reusable inverse actuator model on various occasions will be described in more detail below.

In the limiting unit 24, the expansion ratio setpoint PR _t,sp is advantageously saturated before the inverse actuator model 25 is applied. This saturation is advantageously achieved by capping said expansion ratio PR _t,sp at a maximum expansion ratio PR _t,sp,max, according to the maximum allowable pressure P _dt,max downstream of the turbine 2,12 using the following formula Calculate the maximum expansion ratio PR _t,sp,max :

${\mathrm{<span\; class="notranslate">\; PR</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; sp</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; sat</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; min</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; PR</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; sp</span>}}<span\; class="notranslate">\; ,</span>\frac{{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; dt</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; max</span>}}}{{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; dt</span>}}}<span\; class="notranslate">\; )</span>$

After capping, the expansion ratio PR _{t, sp} is replaced by the saturated expansion ratio PR _{t, sp, sat} .

The intermediate expansion ratio setpoint PR _{t,sp is determined by using a summer 23 that sums the open loop expansion ratio setpoint PR t,sp,ol} with the closed loop expansion ratio setpoint PR _{t,sp,cl .}

The open loop expansion ratio setpoint PR _{t,sp ,ol is calculated from the compression ratio setpoint PR c,sp} by a module modeling the system 20 . This module installed in unit 21 and reused on various occasions (referred to as a pre-positioning module) will be described in more detail below.

The closed loop expansion ratio set point PR _{t, sp, cl} uses a loop back on measured or estimated parameters emanating from the system 20 in order to provide feedback control of the method. The closed-loop expansion ratio setpoint PR _{t,sp, cl} is calculated from the error or difference ε _PRc between the compression ratio setpoint PR _{c,sp and the actual obtained compression ratio measurement PR c,m} . This calculation is performed by the first controller module 22 . This controller module installed in unit 22 and reused on a variety of occasions will be described in more detail below.

Referring to Figure 4, in parallel mode the position setting of the bypass actuators 15, 16 is determined by a summer 29 which sums the open loop position set point α _sp,ol with the closed loop position set point α _sp,cl Point α _sp .

The closed loop position setpoint α _sp,cl uses a loopback on measured or estimated parameters emanating from the system 20 in order to provide feedback control of the method. The closed loop position setpoint α _sp,cl is calculated by the second controller module 27 from the error ε _PRc between the compression ratio setpoint PR _c,sp and the compression ratio measurement PR _c,m . The controller module installed in unit 27 is very similar to the controller module used in series mode.

The open loop position setpoint α _sp,ol is calculated from the compression ratio setpoint PR _c,sp by a module modeling the system 20 . This module includes, in order: the pre-positioning module 26, which is installed in unit 26 and is identical to the pre-positioning module 21 of the series mode; and the reverse actuator model, which is installed in the unit 28 and is identical to the reverse actuator model of the series mode 25 is exactly the same. Determining the open loop position setpoint α _sp,ol comprises the following sequential steps: determining the open loop expansion ratio setpoint PR t _{,sp,ol from the compression ratio setpoint PR c ,sp} by the prepositioning module 26; The inverse actuator model in unit 28 determines the open loop position setpoint α _{sp,ol from the thus determined open loop expansion ratio setpoint PR t,sp, ol} .

The saturation performed in unit 24 in series mode for the expansion ratio parameter PR _t,sp (optional) is here performed in unit 32 for the position parameter α _sp of the bypass actuators 15, 16, the main maximum position set point The parameter α _sp,max corresponds to the same acceptable maximum pressure P _dt,max in the exhaust duct downstream of the turbine 2 , 12 . This saturation is performed according to the following formula:

α _{sp, sat} = min(α _sp , α _{sp, max} )

where α _sp,sat is the position set point after saturation, α _sp is the position set point before saturation, and α _sp,max is the maximum position set point.

This maximum position setpoint α _sp,max is determined from the open loop expansion ratio PR _t,sp,ol using the inverse actuator model installed in unit 31 . This inverse actuator model is the same as that installed in units 28 and 25 of the series model.

Advantageously, the open loop expansion ratio is set in unit 31 according to the maximum allowable pressure P _{dt ,max downstream of the turbine 2,12 before applying the inverse actuator model 31 for determining the maximum position set point α sp,} max Point PR _{t, sp, ol} saturation.

Specific modules common to both series and parallel modes, namely the pre-positioning module, the controller and the inverse actuator model, will now be described in more detail.

A pre-positioning module installed in units 21 and 26 determines the expansion ratio set point from the compression ratio set point. It relies on the assumption that the power of the compressor and turbine are equal in steady state. It can be divided into four steps.

Step 1: Calculate Turbocharger Speed Setpoint

The speed setpoint is calculated from a function f1 given in the form of a compressor map f1 and provided by the manufacturer according to parameters simplified or corrected for pressure and temperature relative to a reference value. This mapping is given in Figures 6 to 9. It gives the compression ratio PR _c at the compressor wheel 3 , 13 as a function of the corrected flow W _c,m,cor and the corrected speed N _sp,cor of the associated compressor. Since the speed N defined for the turbine 2, 12 or the compressor 3, 13 is the same, it can be the corrected Nsp _,cort with respect to the temperature T _ut of the turbine 2, 12, or alternatively with respect to the compressor 3, 13 Corrected Nsp _,corc for temperature _Tuc .

This gets:

PR _c,sp =f ₁ (W _c,m,cor ,N _sp,corc ), and

$N_{\mathrm{sp},\mathrm{corc}}=N_{\mathrm{sp}}\&CenterDot;\sqrt{\frac{T_{c,\mathrm{ref}}}{T_{\mathrm{uc}}}},$ as well as $W_{c,m,\mathrm{cor}}=W_{c,m}\&CenterDot;\sqrt{\frac{T_{\mathrm{uc}}}{T_{c,\mathrm{ref}}}}\frac{P_{c,\mathrm{ref}}}{P_{\mathrm{dc}}}$

The flow rate W _c,m,cor of the intake air 5 is obtained from the previous formula from the air flow rate W _c,m,cor . This flow W _c,m,cor is measured, for example, by a flow meter 9 . It is assumed that the flow through the low-pressure compressor 13 is the same as the flow through the high-pressure compressor 3 .

The turbocharger speed setpoint _Nsp is thus obtained from the compression ratio setpoint PR _c,sp and the flow rate Wc _,m by inversion of the function f1.

Step 2: Calculate Compressor Power Setpoint

The power of the compressor 3 , 13 is expressed analytically by applying the basic principles of thermodynamics to the impeller of the compressor 3 , 13 . This produces expressions showing the extreme pressure conditions of the compressors 3, 13, the flow Wc _,m through the compressors 3, 13 and the upstream temperature _Tuc :

${\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; sp</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; W</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; \&CenterDot;</span>{\mathrm{<span\; class="notranslate">\; Cp</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}}<span\; class="notranslate">\; \&CenterDot;</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{{\mathrm{<span\; class="notranslate">\; \&eta;</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}}}<span\; class="notranslate">\; \&CenterDot;</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; uc</span>}}<span\; class="notranslate">\; [</span>{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; PR</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; sp</span>}}<span\; class="notranslate">\; )</span>}^{\frac{{\mathrm{<span\; class="notranslate">\; \&gamma;</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{{\mathrm{<span\; class="notranslate">\; \&gamma;</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}}}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; ]</span>$

The efficiency η _c in the above expression is related to the speed N _sp and the flow rate W _c,m . This relationship is given by a function f2 established by the manufacturer, eg in the form of a map f2. Such mappings are given in Figures 10 to 13.

${\mathrm{<span\; class="notranslate">\; \&eta;</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; W</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; \&CenterDot;</span>\frac{{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; ref</span>}}}{{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; uc</span>}}}\sqrt{\frac{{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; uc</span>}}}{{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; ref</span>}}}}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; sp</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>\sqrt{\frac{{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; ref</span>}}}{{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; uc</span>}}}}<span\; class="notranslate">\; )</span>$

At this stage, the pressure ratio set point PR _c,sp , the flow measurement W _c,m and the speed set point N _sp are known. The compressor power setpoint Hc _,sp can thus be calculated. This power Hc _,sp consumed by the compressors 3, 13 corresponds to the power that must be made up by the turbines 2, 12 and passed on to the compressors 3, 13 in order to obtain the desired boost pressure P in the intake manifold 6 _{dt, HP} .

Step 3: Calculate Turbine Power

Step 3 converts the compressor power setpoint Hc _,sp to the turbine power setpoint Ht _,sp . The rotational speed N of the turbocharger 1 , 11 is obtained by the dynamics fundamentals applied to the system comprising the turbine 2 , 12 , the compressor 3 , 13 and the shaft coupling the turbine and compressor together. This relationship allows the transition from an "intake" set point (on the compressor) to an "exhaust" set point (on the turbine). The speed N of the turbocharger 1 , 11 basically depends on the difference between the power H _t of the turbine 2 , 12 and the power H _c of the compressor 3 , 13 . These powers can be expressed analytically by applying the first law of thermodynamics. In the following equation, the power is replaced by its set point value:

$\mathrm{<span\; class="notranslate">\; JN</span>}\frac{\mathrm{<span\; class="notranslate">\; dN</span>}}{\mathrm{<span\; class="notranslate">\; dt</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; sp</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; sp</span>}}$

where J is the moment of inertia or the second moment of area and d/dt is the differential operator with respect to time.

Assume the system is in equilibrium. This means that dynamic items can be ignored. Based on this assumption, all turbine power is delivered to the compressor:

Ht _,sp = Hc _,sp

Step 4: Calculate the Open Loop Expansion Ratio Set Point

The turbine power H _t,sp is known and explicitly depends on the expansion ratio PR _t,sp using the following formula:

$h_{t,\mathrm{sp}}=W_{t,\mathrm{sp}}\&CenterDot;{\mathrm{Cp}}_t\&CenterDot;{\mathrm{\&eta;}}_t\&CenterDot;T_{\mathrm{out}}[1-{\left(\frac{1}{{\mathrm{PR}}_{t,\mathrm{sp},\mathrm{ol}}}\right)}^{\frac{{\mathrm{\&gamma;}}_t-1}{{\mathrm{\&gamma;}}_t}}],$ and

$\left\{\begin{array}{c}{\mathrm{<span\; class="notranslate">\; \&eta;</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; PR</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; sp</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; ol</span>}}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; sp</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>\sqrt{\frac{{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; ref</span>}}}{{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; out</span>}}}}<span\; class="notranslate">\; )</span>\\ {\mathrm{<span\; class="notranslate">\; W</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; sp</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>\sqrt{\frac{{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; out</span>}}}{{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; ref</span>}}}}<span\; class="notranslate">\; \&Center\; Dot;</span>\frac{{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; ref</span>}}}{{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; dt</span>}}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; PR</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; sp</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; ol</span>}}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; sp</span>}}<span\; class="notranslate">\; \&CenterDot;</span>\sqrt{\frac{{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; ref</span>}}}{{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; out</span>}}}}<span\; class="notranslate">\; )</span>\end{array}\right.$

This formula can be written as a function of the expansion ratio set point PR _t,sp and inverted to calculate the turbo expansion ratio set point PR _t,sp .

In the following turbine power expression, the flow rate W _t,sp and the efficiency η _t are given by the functions f3 and f4 provided in the form of a map established by the manufacturer of the turbocharger 1 , 11 . They depend on the turbine speed N and the expansion ratio PR _t . The equation expressing the equality of the power setpoints can be rewritten, replacing the turbine power setpoint Ht _,sp with the expression for the turbine power setpoint Ht _,sp :

${\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; sp</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; W</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; sp</span>}}<span\; class="notranslate">\; \&CenterDot;</span>{\mathrm{<span\; class="notranslate">\; Cp</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; \&CenterDot;</span>{\mathrm{<span\; class="notranslate">\; \&eta;</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; \&CenterDot;</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; out</span>}}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>{<span\; class="notranslate">\; (</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{{\mathrm{<span\; class="notranslate">\; PR</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; sp</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; ol</span>}}}<span\; class="notranslate">\; )</span>}^{\frac{{\mathrm{<span\; class="notranslate">\; \&gamma;</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{{\mathrm{<span\; class="notranslate">\; \&gamma;</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}}}}<span\; class="notranslate">\; ]</span>$

Then, if flow and efficiency are replaced by their corresponding expressions, we get:

${\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; sp</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; Cp</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; \&CenterDot;</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; out</span>}}<span\; class="notranslate">\; \&CenterDot;</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; PR</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; sp</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; ol</span>}}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; sp</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; cort</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&CenterDot;</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; PR</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; sp</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; ol</span>}}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; sp</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; cort</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&CenterDot;</span>\frac{{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; dt</span>}}}{{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; ref</span>}}}<span\; class="notranslate">\; \&Center\; Dot;</span>\sqrt{\frac{{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; ref</span>}}}{{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; out</span>}}}}<span\; class="notranslate">\; \&Center\; Dot;</span><span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>{<span\; class="notranslate">\; (</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{{\mathrm{<span\; class="notranslate">\; PR</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; sp</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; ol</span>}}}<span\; class="notranslate">\; )</span>}^{\frac{{\mathrm{<span\; class="notranslate">\; \&gamma;</span>}}_{\mathrm{<span\; class="notranslate">\; r</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{{\mathrm{<span\; class="notranslate">\; \&gamma;</span>}}_{\mathrm{<span\; class="notranslate">\; r</span>}}}}<span\; class="notranslate">\; ]</span>$

Finally, the above relationship can be inverted to calculate the required expansion ratio set point PR _t,sp,ol to obtain the desired compressor power H _c,sp , and this in turn will allow the compression ratio set point PR _{c, sp} and thus obtain the desired lift pressure P _dt,sp .

${\mathrm{<span\; class="notranslate">\; PR</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; sp</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; ol</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; f</span>}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; (</span>\frac{{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; sp</span>}}}{{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; \&CenterDot;</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; out</span>}}<span\; class="notranslate">\; \&CenterDot;</span>\frac{{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; dt</span>}}}{{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; ref</span>}}}<span\; class="notranslate">\; \&CenterDot;</span>\sqrt{\frac{{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; ref</span>}}}{{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; out</span>}}}}}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; sp</span>}}<span\; class="notranslate">\; \&CenterDot;</span>\sqrt{\frac{{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; ref</span>}}}{{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; out</span>}}}}<span\; class="notranslate">\; )</span>$

Map F ^-1 combines maps f3 and f4.

An example of such a mapping F ^-1 is shown in FIGS. 14 to 17 .

The parameters used in the above formulas are input set point parameters or determined by the above formulas. They can even be constants. Therefore, the thermodynamic parameters:

Cp _t (specific heat capacity of exhaust gas 7 at constant pressure) is equal to 1136J/kg/K,

γ _t (which is the coefficient of the ratio Cp _t /Cv _t of the specific heat capacity of the exhaust gas 7 at constant pressure and constant volume respectively) is equal to 1.34,

Cp _c (specific heat capacity of intake air 5 at constant pressure) is equal to 1005J/kg/K,

γ _c (which is the coefficient of the ratio Cp _c /Cv _c of the specific heat capacity of the intake air 5 at constant pressure and constant volume, respectively) is equal to 1.4.

In terms of other parameters involved:

P _dt,max is a constant determined by the tract strength calculation,

W _c,m is determined by the flowmeter by keeping in mind the conservation of mass and the assumption that W _c,m,HP is equal to W _c,m,BP .

_Pdt , _Pdc , _Tuc , _Tut are determined by sensors, estimators or using other methods known to those skilled in the art. Thus, the temperature T _ut upstream of the turbine can be known from the map as a function of the engine speed RM and the load of the engine 4 .

In the illustrative example provided, the reference temperature and pressure used to determine the corrected simplified parameters are equal to:

T _c,ref =298K, T _t,ref =873K, P _c,ref =P _t,ref =1 atmosphere.

This applies to both the high-pressure turbocharger 1 and the low-pressure turbocharger 11 .

The controller is another module that is reused in various embodiment modes. The first controller module 22 is used in series mode and the second controller module 27 is used in parallel mode. The function of such a regulator is (as known) to modify the output parameter (in this case PR _{t, sp} or α _sp ) in order to cancel the difference ε _PRc measured at the input. Those skilled in the art know various methods for performing such functions. Also explained is the case where the controller is a regulator 22, 27 using fuzzy logic rules. Typically, regulators 22, 27 may include proportional-integral-derivative (or PID) modules.

Another module that is reused in various embodiment modes is the module that models the bypass actuators 15 , 16 . Such an actuator located in a channel can be proportionally controlled by a set point α _sp in order to modify the cross-sectional area S _act of the actuator opening between 0 and 100%. For example, such modeling is achieved with the Saint-Venant equation using the following formula:

$W_{\mathrm{act}}=S_{\mathrm{act}}\frac{P_{\mathrm{dt}}}{\sqrt{T_{\mathrm{dt}}}}\&CenterDot;\mathrm{\&psi;}\left(\mathrm{PR}\right),$ in

PR means input parameters, namely, the following parameters respectively:

PR _{t, sp} expansion ratio set point,

PR _{t, sp, ol} open loop expansion ratio set point,

PR _t,sp,ol,sat open loop expansion ratio set point after saturation,

W _act is the flow through the actuator 15, 16,

S _act is the cross-sectional area of the actuator 15, 16,

P _dt is the pressure measurement downstream of the turbine,

T _dt is the temperature measurement downstream of the turbine,

ψ is a function of the variable X and is defined by:

$\mathrm{\&psi;}\left(x\right)=\sqrt{\frac{2{\mathrm{\&gamma;}}_t}{R({\mathrm{\&gamma;}}_t-1)}}\sqrt{x^{\frac{-2}{{\mathrm{\&gamma;}}_t}}-x^{\frac{-({\mathrm{\&gamma;}}_t-1)}{{\mathrm{\&gamma;}}_t}}},$ in

γ _t is the first thermodynamic constant of the exhaust (7), equal to 1.4,

R is the universal gas constant, equal to 287J/kg/K.

In the above formula, due to the conservation of mass, the flow W _act through the actuators 15, 16 can be determined using the following formula:

W _act =W _c,m -W _t,sp , where

W _c,m is the measured flow through the compressor 3, 13,

W _{t, sp} is the flow set point for the flow through the turbine 2 , 12 .

Advantageously, in order to be able to more quickly determine the value of the cross-sectional area S _act of the actuator 15, 16, said cross-sectional area can be mapped to the position set point α _sp and the expansion ratio set point of said actuator 15, 16 Function of PR _{t, sp} .

The description so far relates to a method for operating a turbocharger 1 , 11 . In the presence of twin turbochargers and a bypass valve 14 as shown in FIG. 2, a method for sequentially controlling each of the two turbochargers 1, 11 can be used, so The twin turbochargers include a high-pressure first turbocharger 1 and a low-pressure second turbocharger 11 . The high-pressure first turbocharger 1 comprises: a high-pressure turbine 2 driven by the exhaust gas 7 discharged from the internal combustion engine 4; a high-pressure compressor 3 rotated by said high-pressure turbine 2 to compress the intake air 5 entering said internal combustion engine 4; The high-pressure bypass actuator 15 is used to bypass the high-pressure turbine 2 so that it can control the air flow W _act,HP that does not pass through the high-pressure turbine 2 . The low-pressure second turbocharger 11 includes: a low-pressure turbine 12, driven by the exhaust gas 7 discharged from the internal combustion engine 4 via the high-pressure turbine 2 or the high-pressure bypass actuator 15; a low-pressure compressor 13, driven by the a low-pressure turbine 12 driven in rotation so as to compress the intake air 5 entering the internal combustion engine 4 via the high-pressure compressor 3; and a low-pressure bypass actuator 16 for bypassing the low-pressure turbine 12 so that it can control Air flow W _act,BP of the low-pressure turbine 12 . The bypass valve 14 of the high pressure compressor 3 is used to allow the high pressure compressor 3 to be selectively bypassed in order to connect the low pressure compressor 13 directly to the engine 4 . Such methods determine a set point α _st,HP for controlling said high pressure bypass actuator 15 and a set point α st, _BP for controlling said low pressure bypass actuator 16 according to: high pressure pressure ratio Set point PR _{c, sp, HP} , low pressure pressure ratio set point PR _{c, sp, BP} , air flow W _{c, m} of air through the compressor, temperature T _uc upstream of compressor 3, 13, turbine 2, 12 upstream temperature T _ut .

One embodiment mode of such a method is shown in FIG. 5 . The processing module 19 arbitrates between two separate circuits, each dedicated to the bypass actuators through the turbochargers 1, 11 (ie, the high pressure bypass actuator 15 and the low pressure bypass actuator 16) respectively. One of the turbochargers 1, 11 is controlled. Only one of the two turbochargers 1 , 11 (determined by the processing module 19 ) is operated at any one time. The processing module 19 thus determines _the necessary inputs and _, with the high pressure turbocharger 1 operating, determines the high pressure bypass position set point α _sp,HP of the road actuator 15, or in the case of operating the low pressure turbocharger 11, from the low pressure compression ratio set point PR _c,sp,BP and the low pressure compression ratio measurement PR _{c,m ,BP} determines the position set point α _sp,BP of the low pressure bypass actuator 16 . Each of the two position setpoints α _sp,HP , α _sp,BP is determined according to one of the embodiment modes of the method described above.

Accordingly, the processing module 19 determines which of the high pressure 1 or low pressure 11 turbochargers to operate. It is possible that the processing module 19 receives either the high pressure position setpoint α _sp,HP determined by the high pressure module 17 or the low pressure position setpoint α _sp,BP determined by the low pressure module 18 .

When the high-pressure turbocharger 1 is operating, the processing module 19 uses the setpoint α _{sp, HP} operates the high-pressure actuator 15, uses α _{sp at 0%, the BP} command forces the low-pressure actuator 16 into the closed position, and uses the command β The high pressure valve 14 is forced into the closed position.

When the low-pressure turbocharger 11 is operating, the processing module 19 operates the low-pressure actuator 16 using the setpoint αsp _{, BP} , commands _{the HP} actuator 16 using αsp at 100% to force the high-pressure actuator 15 into the open position, and uses the command β The high pressure valve 14 is forced into an open position.

The input unit 35 can be used to adjust the set point or measure the input parameters PR _{c, sp, HP} , PR _{c, m, HP} , PR _{c, sp, BP} and PR _{c, m} on the basis of more fundamental parameters such as pressure _{, the shape of BP} . Thus, the main set point is the boost pressure or pressure P _dc,sp,HP downstream of the high pressure compressor 3 . A measure of this same parameter P _dc,m,HP (also denoted P _dc,HP ) can also be measured or estimated from the controlled system 20 . A pressure measurement P _uc,m,HP (also denoted P _uc,HP ) upstream of the high pressure compressor 3 can also be provided by measurement or estimation. This means that the input parameters of the high voltage module 17 can be calculated via the summer 33 using the following formula:

${\mathrm{PR}}_{c,\mathrm{sp},\mathrm{HP}}=\frac{P_{\mathrm{uc},m,\mathrm{HP}}}{P_{\mathrm{dc},\mathrm{sp},\mathrm{HP}}},$ ${\mathrm{PR}}_{c,m,\mathrm{HP}}=\frac{P_{\mathrm{uc},m,\mathrm{HP}}}{P_{\mathrm{dc},m,\mathrm{HP}}}$ and

ε _{PRc, HP} = PR _{c, sp, HP} - PR _{c, m, HP}

Other useful parameters _Wc,m,HP , _Pdt,HP , _Pdc ,HP, _Tut,HP , _Tuc,HP are obtained by sensors, estimators or maps.

For the low-voltage module, P _{dc, sp, BP} , P _{dc, m, BP} and P _{uc, m, BP} need to be known. When the low pressure turbocharger 11 is operating, the compressor bypass valve 14 is open. The low pressure downstream pressure Pdc _,sp,BP is then equal to the lift pressure or equal to the known high pressure downstream pressure Pdc _,sp,HP . Likewise, for measurements, this parameter P _dc,m,BP =P _dc,m,HP . The low-pressure upstream pressure P _uc,m,BP is equal to the intake pressure 5, which is equal to the atmospheric pressure P _atm which is 1 atmosphere. This means that the input parameters of the low voltage module 18 can be calculated via the summer 33 using the following formula:

${\mathrm{PR}}_{c,\mathrm{sp},\mathrm{BP}}=\frac{P_{\mathrm{uc},m,\mathrm{BP}}}{P_{\mathrm{dc},\mathrm{sp},\mathrm{BP}}}=\frac{P_{\mathrm{atm}}}{P_{\mathrm{dc},\mathrm{sp},\mathrm{HP}}},$ ${\mathrm{PR}}_{c,m,\mathrm{BP}}=\frac{P_{\mathrm{uc},m,\mathrm{BP}}}{P_{\mathrm{dc},m,\mathrm{HP}}}$ and

ε _{PRc, BP} = PR _{c, sp, BP} - PR _{c, m, BP}

Obtain other useful parameters _Wc,m,BP , _{Pdc,BP,Pdc,BP} , _{Tut, BP} ,Tuc, _BPfrom sensors, estimators or maps.

The step of selecting a turbocharger 1, 11 is performed by the processing module 19 according to the following rules:

- When the speed RM of the engine 4 is below a threshold value, the high pressure turbocharger 1 is operated via the high pressure bypass actuator 15, the bypass valve 14 for bypassing the high pressure compressor 3 is forced closed and the low pressure bypass actuator is forced closed Agency 16,

- When the speed RM of the engine 4 is higher than a threshold value, the low pressure turbocharger 11 is operated via the low pressure bypass actuator 16, the bypass valve 14 for bypassing the high pressure compressor 3 is forced open and the high pressure bypass actuator is forced open Agency15.

The threshold value for the speed of the engine 4 is for example equal to 2750 rpm.

A more elaborate strategy of switching between high and low pressure, eg taking into account engine load, could alternatively be used. A hysteresis may advantageously be introduced to avoid switching too frequently around an engine speed threshold.

The results obtained using the method according to the invention are shown in the graphs of FIGS. 18 and 19 . All curves plot lift pressure versus time during a transient, here at a gear ratio of 3 load. The reference/baseline corresponds to the prior art double loop method. Curve 36 shows a reference lift pressure set point P _dc,sp,HP . Curve 37 shows the boost pressure set point P _dc,sp,HP for series mode. Curve 38 shows a reference lift pressure measurement P _dc,m,HP . Curve 39 shows the boost pressure measurement P _dc,m,HP in series mode. Curve 40 shows a reference boost pressure setpoint P _dc,sp,HP . Curve 41 shows the boost pressure set point P _dc,sp,HP for parallel mode. Curve 42 shows a reference lift pressure measurement P _dc,m,HP . Curve 43 shows the boost pressure measurement P _dc,m,HP in parallel mode.

The described method shows that a two-stage supercharging system can be adjusted regardless of the pressure in the exhaust manifold 8 of the engine 4 . "Single loop" series and parallel configurations have very similar performance to each other. Furthermore, the "single loop" structure makes it possible to obtain almost exactly the same response times as the reference "dual loop" method.

Claims (19)

1. one kind is used for turbosupercharger (1,11) so that the method that internal-combustion engine (4) is carried out supercharging, and said turbosupercharger (1,11) comprising: turbine (2,12) is driven by exhaust (7); Compressor (3,13), by said turbine (2,12) rotary driving so that compress inlet air (5); And bypass actuator (15,16), be used to walk around said turbine (2,12), make it can control without the air mass flow (W of said turbine (2,12) _Act), it is characterized in that said method comprises the position set point (α that confirms said bypass actuator (15,16) according to following _Sp) step: compression ratio set point (PR _{C, sp}), compression ratio measures (PR _{C, m}), the flow measurement (W of the flow through said compressor (3,13) _{C, m}), the pressure measurement (P of the pressure in said turbine (2,12) downstream _Dt), the pressure measurement (P of the pressure in said compressor (3,13) downstream _Dc), the thermometry (T of the temperature at said turbine (2, the 12) upper reaches _Ut) and the thermometry (T of the temperature at said compressor (3, the 13) upper reaches _Uc), said step comprises:

-according to said compression ratio set point (PR _{C, sp}) and said compression ratio measurement (PR _{C, m}) confirm expansion ratio set point (PR _{T, sp}),

-according to the expansion ratio set point (PR that so confirms _{T, sp}) confirm the position set point (α of said bypass actuator (15,16) _Sp).

2. the method described in claim 1 is wherein according to said expansion ratio set point (PR _{T, sp}) confirm the position set point (α of said bypass actuator (15,16) _Sp) use against actuator's model (25).

3. the method described in claim 2 wherein using said contrary actuator's model (25) before, is used the maximum allowable pressure (P of following formula according to said turbine (2,12) downstream _{Dt, max}) make said expansion ratio set point (PR _{T, sp}) saturated:

${\mathrm{PR}}_{t,\mathrm{Sp},\mathrm{Sat}}=\mathrm{Min}({\mathrm{PR}}_{t,\mathrm{Sp}},\frac{P_{\mathrm{Dt},\mathrm{Max}}}{P_{\mathrm{Dt}}}),$ Wherein

PR _{T, sp, sat}Be saturated expansion ratio set point afterwards,

PR _{T, sp}Be saturated expansion ratio set point before,

P _DtBe the pressure in said turbine (2,12) downstream,

P _{Dt, max}The maximum that is said turbine (2,12) downstream can be accepted pressure,

Compression ratio set-point value (PR after saturated _{T, sp, sat}) will replace initial compression afterwards than set-point value (PR _{T, sp}).

4. the method described in the arbitrary claim in the claim 1 to 3, wherein said expansion ratio set point (PR _{T, sp}) equal by preposition module (21) according to said compression ratio set point (PR _{C, sp}) the open loop expansion ratio set point (PR that calculates _{T, sp, ol}) with by first controller module (22) according to said compression ratio set point (PR _{C, sp}) and said compression ratio measurement (PR _{C, m}) between error (ε _PRc) the closed loop expansion ratio set point (PR that calculates _{T, sp, cl}) with.

5. the method described in claim 1, the position set point (α of wherein said bypass actuator (15,16) _Sp) equal according to said compression ratio set point (PR _{C, sp}) the open loop position set point (α that calculates _{Sp, ol}) with by second controller module (27) according to said compression ratio set point (PR _{C, sp}) and said compression ratio measurement (PR _{C, m}) between error (ε _PRc) the closed loop position set point (α that calculates _{Sp, cl}) with.

6. the method described in claim 5 is wherein confirmed said open loop position set point (α _{Sp, ol}) may further comprise the steps:

-by preposition module (26) according to said compression ratio set point (PR _{C, sp}) confirm open loop expansion ratio set point (PR _{T, sp, ol}),

-use contrary actuator's model (28) according to the open loop expansion ratio set point (PR that so confirms _{T, sp, ol}) confirm open loop position set point (α _{Sp, ol}).

7. the method described in claim 5 or 6 wherein uses following formula finally to make said position set point (α _Sp) saturated:

α _{Sp, sat}=min (α _Sp, α _{Sp, max}), wherein

α _{Sp, sat}Be saturated position set point afterwards,

α _SpBe saturated position set point before,

α _{Sp, max}It is the maximum position set point.

8. the method described in claim 7 wherein uses contrary actuator's model (31) according to said open loop expansion ratio set point (PR _{T, sp, ol}) confirm said maximum position set point (α _{Sp, max}).

9. the method described in claim 8 wherein is used for confirming said maximum position set point (α in application _{Sp, max}) contrary actuator model (31) before, use the maximum allowable pressure (P of following formula according to said turbine (2,12) downstream _{Dt, max}) make said open loop expansion ratio set point (PR _{T, sp, pl}) saturated:

${\mathrm{PR}}_{t,\mathrm{Sp},\mathrm{Sat}}=\mathrm{Min}({\mathrm{PR}}_{t,\mathrm{Sp},\mathrm{Ol}},\frac{P_{\mathrm{Dt},\mathrm{Max}}}{P_{\mathrm{Dt}}}),$ Wherein

PR _{T, sp, sat}Be saturated expansion ratio set point afterwards,

PR _{T, sp}Be saturated expansion ratio set point before,

P _DtBe the pressure in said turbine (2,12) downstream,

P _{Dt, max}The maximum that is said turbine (2,12) downstream can be accepted pressure,

Expansion ratio set-point value (PR after saturated _{T, sp, sat}) will replace initial open loop expansion ratio set-point value (PR afterwards _{T, sp, ol}).

10. the method described in the arbitrary claim in claim 4 or 6 to 9, wherein said preposition module (21,26) may further comprise the steps:

The following formula of-use is according to the flow measurement (W of the flow of the air inlet (5) of passing through said compressor (3,13) _{C, m}) confirm the flow measurement (W after the correction of flow of the air inlet (5) through said compressor (3,13) _{C, m, cor}):

$W_{c,m,\mathrm{Cor}}=W_{c,m}\&CenterDot;\sqrt{\frac{T_{\mathrm{Uc}}}{T_{c,\mathrm{Ref}}}}\&CenterDot;\frac{P_{c,\mathrm{Ref}}}{P_{\mathrm{Dc}}},$ Wherein

W _{C, m, cor}Be the flow measurement after the correction of flow of the air inlet (5) through said compressor (3,13),

W _{C, m}Be the air-flow measurement of the flow of the air inlet (5) through said compressor (3,13),

T _UcBe the temperature at said compressor (3, the 13) upper reaches,

P _UcBe the pressure at said compressor (3, the 13) upper reaches,

T _{C, ref}Be the reference temperature of said compressor (3,13),

P _{C, ref}Be the reference pressure of said compressor (3,13),

-use said compression ratio (PR _c) and the correction of the air inlet (5) through said compressor (3,13) after flow (W _{C, cor}) function (f1) confirm the speed set point (N after the relevant correction of said compressor (3,13) _{Sp, corc}), said function (f1) is defined by two-dimensional map,

-use following formula basis about the speed set point (N after the correction of said compressor (3,13) _{Sp, corc}) confirm speed set point (N _Sp),

Wherein

N _SpBe the speed set point of said turbosupercharger (1,11),

N _{Sp, corc}Be the speed set point after the correction of relevant said compressor (3,13) of said turbosupercharger (1,11),

T _UcBe the temperature at said compressor (3, the 13) upper reaches,

T _{C, ref}Be the reference temperature of said compressor (3,13),

-use the speed set point (N after the correction of relevant said compressor (3,13) of said turbosupercharger (1,11) _{Sp, corc}) and the correction of the flow of the air inlet (5) through said compressor (3,13) after air mass flow set point (W _{C, sp, cor}) function (f2), according to the speed set point (N after the correction of the relevant said compressor (3,13) of said turbosupercharger (1,11) _{Sp, corc}) and the correction of the flow of the air inlet (5) through said compressor (3,13) after air mass flow set point (W _{C, sp, cor}), calculate the efficient (η of said compressor (3,13) _c), said function (f2) is defined by two-dimensional map,

-use following formula to calculate compressor horsepower set point (H _{C, sp}),

$H_{c,\mathrm{Sp}}=W_{c,m}{\mathrm{Cp}}_c\frac{1}{{\mathrm{\&eta;}}_c}{T}_{\mathrm{Uc}}({\mathrm{PR}}_{c,\mathrm{Sp}}^{\frac{{\mathrm{\&gamma;}}_c-1}{{\mathrm{\&gamma;}}_c}}-1),$ Wherein

H _{C, sp}Be the power setting point of said compressor (3,13),

W _{C, m}Be the air-flow measurement of the flow of the air inlet (5) through said compressor (3,13),

η _cBe the efficient of said compressor (3,13),

T _UcBe the temperature at said compressor (3, the 13) upper reaches,

PR _{C, sp}Be the compression ratio set point of said compressor (3,13),

Cp _cBe first thermodynamic equilibrium constant of air inlet (5),

γ _cBe second thermodynamic equilibrium constant of air inlet (5),

-use following formula to calculate turbine power set point (H _{T, sp}): H _{T, sp}=H _{C, sp}, wherein

H _{T, sp}Be the power setting point of said turbine (2,12),

H _{C, sp}Be the power setting point of said compressor (3,13),

-use following formula according to said speed set point (N _Sp) confirm about the speed set point (N after the correction of said turbine (2,12) _{Sp, cort}):

$N_{\mathrm{Sp},\mathrm{Cort}}=N_{\mathrm{Sp}}\sqrt{\frac{T_{t,\mathrm{Ref}}}{T_{\mathrm{Ut}}}},$ Wherein

N _SpBe the speed set point of said turbosupercharger (1,11),

N _{Sp, cort}Be the speed set point after the correction of relevant said turbine (2,12) of said turbosupercharger (1,11),

T _UtBe the temperature at said turbine (2, the 12) upper reaches,

T _{T, ref}Be the reference temperature of said turbine (2,12),

-use following formula to calculate said open loop expansion ratio set point (PR _{T, sp, ol})

${\mathrm{PR}}_{t,\mathrm{Sp},\mathrm{Ol}}=F^{-1}(\frac{H_{c,\mathrm{Sp}}}{{\mathrm{Cp}}_t\&CenterDot;T_{\mathrm{Ut}}\&CenterDot;\frac{P_{\mathrm{Dt}}}{P_{t,\mathrm{Ref}}}\&CenterDot;\sqrt{\frac{T_{t,\mathrm{Ref}}}{T_{\mathrm{Ut}}}}},N_{\mathrm{Sp},\mathrm{Cort}}),$ Wherein

PR _{T, sp, ol}Be the open loop expansion ratio of said turbine (2,12),

H _{T, sp}Be the power setting point of said turbine (2,12),

N _{Sp, cort}Be the speed set point after the correction of relevant said turbine (2,12) of said turbosupercharger (1,11), and

F is by the function of two-dimensional map definition and the acquisition of inverting through following equation:

$H_{t,\mathrm{Sp}}=W_{t,\mathrm{Sp}}\&CenterDot;{\mathrm{Cp}}_t\&CenterDot;{\mathrm{\&eta;}}_t\&CenterDot;T_{\mathrm{Ut}}[1-{\left(\frac{1}{{\mathrm{PR}}_{t,\mathrm{Sp},\mathrm{Ol}}}\right)}^{\frac{{\mathrm{\&gamma;}}_t-1}{{\mathrm{\&gamma;}}_t}}],$ Wherein

H _{T, sp}Be the power setting point of said turbine (2,12),

PR _{T, sp, ol}Be the open loop expansion ratio of said turbine (2,12),

Cp _tBe first thermodynamic equilibrium constant of exhaust (7),

γ _tBe second thermodynamic equilibrium constant of exhaust (7),

η _tBe the efficient of said turbine (2,12), can be by the speed set point (N after the correction of the relevant said turbine (2,12) of said turbosupercharger (1,11) _{Sp, cort}) and said open loop expansion ratio set point (PR _{T, sp, ol}) function (f3) express, said function (f3) is by two-dimensional map definition,

W _{T, sp}Be the exhaust (7) through said turbine (2,12) flow flow set point and confirm by following formula:

$W_{t,\mathrm{Sp}}=W_{t,\mathrm{Sp},\mathrm{Cor}}\&CenterDot;\sqrt{\frac{T_{t,\mathrm{Ref}}}{T_{\mathrm{Ut}}}}\&CenterDot;\frac{P_{\mathrm{Dt}}}{P_{t,\mathrm{Ref}}},$ Wherein

W _{T, sp}Be the flow set point of the flow of the exhaust (7) through said turbine (2,12),

W _{T, sp, cor}Be the flow set point after the correction of flow of the exhaust (7) through said turbine (2,12), by the speed set point (N after the correction of the relevant said turbine (2,12) of said turbosupercharger (1,11) _{Sp, cort}) and said open loop expansion ratio set point (PR _{T, sp, ol}) function (f4) express, said function (f4) is by two-dimensional map definition,

T _UtBe the temperature at said turbine (2, the 12) upper reaches,

T _{T, ref}Be the reference temperature of said turbine (2,12),

P _DtBe the pressure in said turbine (2,12) downstream,

P _{T, ref}It is the reference pressure of said turbine (2,12).

11. the method described in the arbitrary claim in the claim 4 to 10, wherein said first controller module (22) or correspondingly said second controller module (27) are to be configured to eliminate said error (ε _PRc) regulator (22,27).

12. the method described in claim 11, wherein said regulator (22,27) uses fuzzy logic ordination.

13. the method described in claim 11 or 12, wherein said regulator (22,27) usage ratio integral differential (PID) module.

14. the method described in the arbitrary claim in the claim 2 to 4 and 6 to 13; Wherein use following formula through the St.Venant equation to being used to walk around said turbine (2; 12) bypass actuator (15,16) modeling: wherein

PR representes input parameter,, is respectively following parameter that is:

PR _{T, sp}The expansion ratio set point,

PR _{T, sp, ol}Open loop expansion ratio set point,

PR _{T, sp, ol, sat}Open loop expansion ratio set point after saturated,

W _ActBe flow through said actuator (15,16),

S _ActBe the sectional area of said actuator (15,16),

P _DtBe the pressure in said turbine (2,12) downstream,

T _DtBe the temperature in said turbine (2,12) downstream,

ψ is the function of variable X, is defined by following formula:

$\mathrm{\&psi;}\left(X\right)=\sqrt{\frac{2{\mathrm{\&gamma;}}_t}{R({\mathrm{\&gamma;}}_t-1)}}\sqrt{X^{\frac{-2}{{\mathrm{\&gamma;}}_t}}-X^{\frac{-({\mathrm{\&gamma;}}_t-1)}{{\mathrm{\&gamma;}}_t}}},$ Wherein

γ _tBe first thermodynamic equilibrium constant of exhaust (7), equal 1.4,

R is a universal gas constant, equals 287J/kg/K.

15. the definite method described in claim 14 is wherein used formula W _Act=W _{C, m}-W _{T, sp}Confirm flow (W through said actuator (15,16) _Act), wherein

W _{C, m}Be measurement through the flow of said compressor (3,13),

W _{T, sp}It is flow set point through the flow of said turbine (2,12).

16. the definite method described in the arbitrary claim in the claim 14 and 15, the said sectional area (S of wherein said actuator (15,16) _Act) be mapped as the said position set point (α of said actuator (15,16) _Sp) and said expansion ratio set point (PR _{T, sp}) function.

17. one kind is used for fixing the two supercharging equipments of geometrical shape so that the method that internal-combustion engine (4) is carried out supercharging, said equipment comprises:

-high pressure first turbosupercharger (1) comprising: high-pressure turbine (2), and the exhaust (7) of being discharged by said internal-combustion engine (4) drives; High pressure compressor (3), by said high-pressure turbine (2) rotary driving so that compression gets into the air inlet (5) of said internal-combustion engine (4); And high pressure turbine by actuator (15), be used to walk around said high-pressure turbine (2), make it can control without the air mass flow (W of said high-pressure turbine (2) _{Act, HP}),

-low pressure second turbosupercharger (11) comprising: low-pressure turbine (12), and the exhaust (7) via said high-pressure turbine (2) or said high pressure turbine by actuator (15) of being discharged by said internal-combustion engine (4) drives; Low pressure compressor (13), by said low-pressure turbine (12) rotary driving so that the air inlet (5) that compression gets into said internal-combustion engine (4) via said high pressure compressor (3); And low voltage bypass actuator (16), be used to walk around said low-pressure turbine (12), make it can control without the air mass flow (W of said low-pressure turbine (12) _{Act, BP}), and

The by-pass valve (14) of-said high pressure compressor (3) is used to allow optionally walk around said high pressure compressor (3) so that said low pressure compressor (13) is directly connected to engine (4),

Said method comprises the set point (α that confirms to be used to control said high pressure turbine by actuator (15) according to following _{St, HP}) and be used to control the set point (α of said low voltage bypass actuator (16) _{St, BP}): high-pressure is than set point (PR _{C, sp, HP}), low pressure is than set point (PR _{C, sp, BP}), high-pressure is than measuring (PR _{C, m, HP}), low pressure is than measuring (PR _{C, m, BP}), the air-flow measurement (W of the air mass flow through high pressure compressor (3) and low pressure compressor (13) _{C, m}), respectively at the pressure measurement (P in said high-pressure turbine (2) and said low-pressure turbine (12) downstream _{Dt, HP}) and (P _{Dt, BP}), respectively at the pressure measurement (P in said high pressure compressor (3) and said low pressure compressor (13) downstream _{Dc, HP}) and (P _{Dc, BP}), respectively at the thermometry (T at the said high-pressure turbine (2) and said low-pressure turbine (12) upper reaches _{Ut, HP}) and (T _{Ut, BP}) and respectively at the thermometry (T at the said high pressure compressor (3) and said low pressure compressor (13) upper reaches _{Uc, HP}) and (T _{Uc, BP}),

It is characterized in that, said method comprising the steps of:

-select to control which the bypass actuator in said high pressure turbine by actuator (15) and the said low voltage bypass actuator (16) by puocessing module (19),

-described in the arbitrary claim in the claim 1 to 16, according to high pressure compressed than set point (PR _{C, sp, HP}) and high pressure compressed ratio measurement (PR _{C, m, HP}) correspondingly select the position set point (α of said high pressure turbine by actuator (15) _{Sp, HP}), perhaps according to low pressure compression ratio set point (PR _{C, sp, BP}) and low pressure compression ratio measurement (PR _{C, m, BP}) confirm the position set point (α of said low voltage bypass actuator (16) _{Sp, BP}).

18. the method described in claim 17 is wherein carried out according to following rule by said puocessing module (19) and is selected step:

-when the speed (RM) of said engine (4) when being lower than threshold value, making said high pressure turbine by actuator (15) operation, the by-pass valve (14) of said high pressure compressor (3) is forced closed and said low voltage bypass actuator (16) is forced closed,

-when the speed (RM) of said engine (4) when being higher than threshold value, making said low voltage bypass actuator (16) operation, the by-pass valve (14) of said high pressure compressor (3) is forced to be opened and said high pressure turbine by actuator (15) is forced and opens.

19. the method described in claim 18, the threshold velocity (RM) of wherein said engine (4) equals 2750rpm.

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